Vacuum cleaners which utilise cyclonic separating apparatus are well known. Examples of such vacuum cleaners are shown in EP 0042723, U.S. Pat. No. 4,373,228, U.S. Pat. No. 3,425,192, U.S. Pat. No. 6,607,572 and EP 1268076. In each of these arrangements, first and second cyclonic separating units are provided with the incoming air passing sequentially through each separating unit. In some cases, the second cyclonic separating unit includes a plurality of cyclones arranged in parallel with one another.